The slackware suggestion makes a lot of sense. Especially considering the
fact that it is the only distribution compiling packages with optimisations
for i486 ! Most newer distributions will use optimisations for i686 at least
which assumes pipeline structure, which simply will not work on a old
machine.
Using slackware and proceeding in a way Aditya suggests (install base and
increment only what you need) should work best for you. On another note,
Redhat is a poor choice for low end machines. Being an enterprise-geared
distribution, it will take a lot of tweaking disabling daemons and kernel
services like SE-Linux to get it speeding along on a Pentium with 64 MB RAM.
My 2 cents.
Cheers,
Manas